1. Field of the Invention
The invention relates to a dry gas sealing system for a turbomachine and to a turbomachine comprising such a dry gas sealing system.
2. Description of the Prior Art
In turbomachines, such as for example turbocompressors, dry gas seals are increasingly employed that supersede conventional oil film seals for sealing a rotor-side component of the turbomachine relative to a stator-side component of the turbomachine.
FIGS. 1 and 2 show details of a dry gas sealing system known from the prior art, which serves for sealing a rotor-side component 2 of a turbomachine relative to a stator-side component 3 of the same. In FIG. 1, two dry gas seals 4 are shown that seal the rotor-side component 2 relative to the stator-side component 3, wherein each of the dry gas seals 4 comprises a sealing device 5 consisting of a rotor-side sealing element 5 and a stator-side sealing element 7. The respective stator-side sealing element 7 of the sealing device 5 of the respective dry gas seal 4 is fastened to a stator-side support device 8 of the respective dry gas seal 4 and is pressed or pushed against the rotor-side sealing element 6 with a defined force via a spring element 9, which is supported between the respective stator-side support device 8 and the stator-side component. Because of this, the stator-side sealing element 7 lies against the rotor-side sealing element 6 in a defined manner.
Thus, each of the dry gas seals 4 of the dry gas sealing system is supplied on the one hand with so-called seal gas 10, wherein the seal gas 10 is cleaned process gas 11, which is extracted from the turbomachine 12 and conducted via a cleaning device 13 for cleaning. Furthermore, each dry gas seal 4 is supplied with two further gas flows, namely buffer gas 14 and separation gas 15. The buffer gas 14 and separation gas 15 are for example N2, which is kept ready in a storage tank 25 and following conditioning is supplied to the respective dry gas seal 4 via a suitable regulating device 26.
The gas recirculations of a dry gas seal are a leakage 16 of the seal gas 10, which is recirculated to the turbomachine 12 and thus to the process, a leakage 17 of a mixture of seal gas 10 and buffer gas 14, which is also called inner leakage, a leakage 18 of a mixture of buffer gas 14 and separation gas 15, which is also called outer leakage, a leakage 19 of the separation gas 15 to the bearing, which is also called bearing leakage.
Accordingly, as already explained above, it is necessary with dry gas sealing systems to extract process gas 11 from the process, i.e. the turbomachine, clean the same in a cleaning device 13 and supply the cleaned process gas 11 to the respective dry gas seal 4 as seal gas 10. In dry gas sealing system known from the prior art, the conditioning of cleaning of the process gas 11 is performed in external filters.